Comparison of central corneal thickness measured by AS-OCT, Pentacam and A-mode ultrasound

Abstract

Objective To compare the difference of central corneal thickness (CCT) measured by anterior segment optical coherence tomography(AS-OCT),Pentacam and A-mode ultrasound.Methods AS-OCT,Pentacam and A-mode ultrasound were used to measure the CCT on 102 myopic cases (204 eyes) undergoing laser in situ keratomileusis (LASIK),and then compared the results.Resulls AS-OCT and Pentacam had better repeatability in measurement of CCT than A-mode ultrasound.The value of CCT measured by AS-OCT,Pentacam and A-mode ultrasound were (532-± 30)μm,(539 ±31)μm and (537 ±29)μm.There was a significant linear correlation in CCT measured by three measurements (P ＜ 0.05).The regression equation of three measurements were CCT Pentacam =0.934 CCT AS-OCT +39.789,CCT Pentacam =0.875 CCT A-mode +70.194 and CCT AS-OCT =0.913 CCT Amode + 40.962.The CCT measured by AS-OCT was obvious lower than that measured by Pentacam and A-mode ultrasound,there were statistical differences (P ＜ 0.05).Conclusions AS-OCT,Pentacam and A-mode ultrasound have different advantage of three measurements on clinical using,these instruments should not be used interchangeably for CCT measurement. Key words: Central corneal thickness; Anterior segment optical coherence tomography; Pentacam ; A-mode ultrasound